If we have a 2+ node cluster which is replicating from an async master
and the binlog_format is set to STATEMENT and multi-row inserts are executed
on a table with an auto_increment column such that values are automatically
generated by MySQL, then the server node generates wrong auto_increment
values, which are different from what was generated on the async master.
The causes and fixes:
1. We need to improve processing of changing the auto-increment values
after changing the cluster size.
2. If wsrep auto_increment_control switched on during operation of
the node, then we should immediately update the auto_increment_increment
and auto_increment_offset global variables, without waiting of the next
invocation of the wsrep_view_handler_cb() callback. In the current version
these variables retain its initial values if wsrep_auto_increment_control
is switched on during operation of the node, which leads to inconsistent
results on the different nodes in some scenarios.
3. If wsrep auto_increment_control switched off during operation of the node,
then we must return the original values of the auto_increment_increment and
auto_increment_offset global variables, as the user has set. To make this
possible, we need to add a "shadow copies" of these variables (which stores
the latest values set by the user).
Adding a FK constraint to an existing table (ALTER TABLE ADD FOREIGN
KEY) causes the applier to fail, if a concurrent DML statement that
violate the new constraint (i.e. a DELETE or UPDATE of record in the
parent table).
For exmaple, the following scenario causes a crash in the applier:
1. ALTER successfully adds FK constraint in node_1
2. On node_2 is UPDATE is in pre_commit() and has certified successfully
3. ALTER is delivered in node_2 and BF aborts DML
4. Applying UPDATE event causes FK violation in node_1
To avoid this situation it is necessary for UPDATE to fail during
certification. And for the UPDATE to fail certfication it is necessary
that ALTER appends certification keys for both the child and the parent
table. Before this patch, ALTER TABLE ADD FK only appended keys for
child table which is ALTERed.
These test can sporadically show mutex deadlock warnings between LOCK_wsrep_thd
and LOCK_thd_data mutexes. This means that these mutexes can be locked in opposite
order by different threads, and thus result in deadlock situation.
To fix such issue, the locking policy of these mutexes should be revised and
enforced to be uniform. However, a quick code review shows that the number of
lock/unlock operations for these mutexes combined is between 100-200, and all these
mutex invocations should be checked/fixed.
On the other hand, it turns out that LOCK_wsrep_thd is used for protecting access to
wsrep variables of THD (wsrep_conflict_state, wsrep_query_state), whereas LOCK_thd_data
protects query, db and mysys_var variables in THD. Extending LOCK_thd_data to protect
also wsrep variables looks like a viable solution, as there should not be a use case
where separate threads need simultaneous access to wsrep variables and THD data variables.
In this commit LOCK_wsrep_thd mutex is refactored to be replaced by LOCK_thd_data.
By bluntly replacing LOCK_wsrep_thd by LOCK_thd_data, will result in double locking
of LOCK_thd_data, and some adjustements have been performed to fix such situations.
Removed including wsrep_api.h from service_wsrep.h. This caused
various kinds of collisions with definitions when wsrep is
not supposed to be built in. Defined functions wsrep_xid_seqno()
and wsrep_xid_uuid() in wsrep_dummy.cc. Replaced wsrep_seqno_t
with long long where wsrep_api.h is not included.
Removed wsrep_xid_seqno() macro from wsrep_mysqld.h and made
wsrep code using wsrep_xid_seqno() in handler.cc to be compiled
in only if WITH_WSREP is ON.
Included wsrep_api.h for mariabackup if WITH_WSREP is ON.
This was done in, among other things:
- thd->db and thd->db_length
- TABLE_LIST tablename, db, alias and schema_name
- Audit plugin database name
- lex->db
- All db and table names in Alter_table_ctx
- st_select_lex db
Other things:
- Changed a lot of functions to take const LEX_CSTRING* as argument
for db, table_name and alias. See init_one_table() as an example.
- Changed some function arguments from LEX_CSTRING to const LEX_CSTRING
- Changed some lists from LEX_STRING to LEX_CSTRING
- threads_mysql.result changed because process list_db wasn't always
correctly updated
- New append_identifier() function that takes LEX_CSTRING* as arguments
- Added new element tmp_buff to Alter_table_ctx to separate temp name
handling from temporary space
- Ensure we store the length after my_casedn_str() of table/db names
- Removed not used version of rename_table_in_stat_tables()
- Changed Natural_join_column::table_name and db_name() to never return
NULL (used for print)
- thd->get_db() now returns db as a printable string (thd->db.str or "")
* changed thd_binlog_format to return configured binlog format in wsrep execution,
regardless of binlogging setting (i.e. with or without binlogging)
* thd_binlog_format is used in innobase::write_row(), and would return confusing
result there when log_bin==OFF
For running the Galera tests, the variable my_disable_leak_check
was set to true in order to avoid assertions due to memory leaks
at shutdown.
Some adjustments due to MDEV-13625 (merge InnoDB tests from MySQL 5.6)
were performed. The most notable behaviour changes from 10.0 and 10.1
are the following:
* innodb.innodb-table-online: adjustments for the DROP COLUMN
behaviour change (MDEV-11114, MDEV-13613)
* innodb.innodb-index-online-fk: the removal of a (1,NULL) record
from the result; originally removed in MySQL 5.7 in the
Oracle Bug #16244691 fix
377774689b
* innodb.create-index-debug: disabled due to MDEV-13680
(the MySQL Bug #77497 fix was not merged from 5.6 to 5.7.10)
* innodb.innodb-alter-autoinc: MariaDB 10.2 behaves like MySQL 5.6/5.7,
while MariaDB 10.0 and 10.1 assign different values when
auto_increment_increment or auto_increment_offset are used.
Also MySQL 5.6/5.7 exhibit different behaviour between
LGORITHM=INPLACE and ALGORITHM=COPY, so something needs to be tested
and fixed in both MariaDB 10.0 and 10.2.
* innodb.innodb-wl5980-alter: disabled because it would trigger an
InnoDB assertion failure (MDEV-13668 may need additional effort in 10.2)
WSREP_LOG increased the stack size of all function, where it was used,
with 1024 bytes, even if it would never called. What's worse is that one
a Mac with Lion 10.7, the stack size was increased with 1024* number of
calls per function.
By moving WSREP_LOG() to a function, the stack size on Lion in function
mysql_execute() was reduced from 18K to 12K. On my main Linux machine
with gcc 5.4 the reduction was from 5k to 4k.
Previously, setting `wsrep_sync_wait = 1` would have an effect on
both SELECT and SHOW statements.
This patch changes wsrep_sync_wait so that bitmask value 1 is used
for SELECT statements, while bitmask value 8 is reserved for SHOW
statements.
It is still possible to achieve sync wait on both SELECT and SHOW
statements by setting `wsrep_sync_wait = 9`.
Previously, setting `wsrep_sync_wait = 1` would have an effect on
both SELECT and SHOW statements.
This patch changes wsrep_sync_wait so that bitmask value 1 is used
for SELECT statements, while bitmask value 8 is reserved for SHOW
statements.
It is still possible to achieve sync wait on both SELECT and SHOW
statements by setting `wsrep_sync_wait = 9`.
Signed-off-by: Jan Lindström <jan.lindstrom@mariadb.com>
Benefits of this patch:
- Removed a lot of calls to strlen(), especially for field_string
- Strings generated by parser are now const strings, less chance of
accidently changing a string
- Removed a lot of calls with LEX_STRING as parameter (changed to pointer)
- More uniform code
- Item::name_length was not kept up to date. Now fixed
- Several bugs found and fixed (Access to null pointers,
access of freed memory, wrong arguments to printf like functions)
- Removed a lot of casts from (const char*) to (char*)
Changes:
- This caused some ABI changes
- lex_string_set now uses LEX_CSTRING
- Some fucntions are now taking const char* instead of char*
- Create_field::change and after changed to LEX_CSTRING
- handler::connect_string, comment and engine_name() changed to LEX_CSTRING
- Checked printf() related calls to find bugs. Found and fixed several
errors in old code.
- A lot of changes from LEX_STRING to LEX_CSTRING, especially related to
parsing and events.
- Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING*
- Some changes for char* to const char*
- Added printf argument checking for my_snprintf()
- Introduced null_clex_str, star_clex_string, temp_lex_str to simplify
code
- Added item_empty_name and item_used_name to be able to distingush between
items that was given an empty name and items that was not given a name
This is used in sql_yacc.yy to know when to give an item a name.
- select table_name."*' is not anymore same as table_name.*
- removed not used function Item::rename()
- Added comparision of item->name_length before some calls to
my_strcasecmp() to speed up comparison
- Moved Item_sp_variable::make_field() from item.h to item.cc
- Some minimal code changes to avoid copying to const char *
- Fixed wrong error message in wsrep_mysql_parse()
- Fixed wrong code in find_field_in_natural_join() where real_item() was
set when it shouldn't
- ER_ERROR_ON_RENAME was used with extra arguments.
- Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already
give the error.
TODO:
- Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c
- Change code to not modify LEX_CSTRING for database name
(as part of lower_case_table_names)
This commit is for optimizing WSREP(thd) macro.
#define WSREP(thd) \
(WSREP_ON && wsrep && (thd && thd->variables.wsrep_on))
In this we can safely remove wsrep and thd. We are not removing WSREP_ON
because this will change WSREP(thd) behaviour.
Patch Credit:- Nirbhay Choubay, Sergey Vojtovich
Tasks:-
Changes in wsrep_dirty_reads variable
1.) Global + Session scope (Current: session-only)
2.) Can be set using command line.
3.) Allow all commands that do not change data (besides SELECT)
4.) Allow prepared Statements that do not change data
5.) Works with wsrep_sync_wait enabled
Tasks:-
Changes in wsrep_dirty_reads variable
1.) Global + Session scope (Current: session-only)
2.) Can be set using command line.
3.) Allow all commands that do not change data (besides SELECT)
4.) Allow prepared Statements that do not change data
5.) Works with wsrep_sync_wait enabled
Tasks:-
Changes in wsrep_dirty_reads variable
1.) Global + Session scope (Current: session-only)
2.) Can be set using command line.
3.) Allow all commands that do not change data (besides SELECT)
4.) Allow prepared Statements that do not change data
5.) Works with wsrep_sync_wait enabled
